Comcast is Auto-drafting someone else's bills and won't stop because we aren't them and don't know who they are

We are a business that has multiple accounts with Comcast.  We had been paying the bills online with our checking account number.  Last fall, an additional account started auto-drafting monthly that we did NOT pay.  For 6 months Comcast has given us the run-around, sending us from billing support to security back to billing repeatedly, telling us they can't talk to us without talking to our bank too.  When we get our bank on the line, they still tell us they can't give us any info because they are unable to access billing payments by date and amount.  We have multiple tickets, have spent countless hours and still can't make the monthly payment stop.  We know it is not fraud because it is the only unknown hitting our bank and would cost thousands dollars and hours of time to change our bank account number over this.  Clearly this is a glitch or issue in the Comcast system.  But- No one is calling us back, no one is helping us and if Comcast can't track it's payments and receipts, then there is clearly a big issue.  They won't even send us over to talk to a manager or supervisor or someone with access to payments.  We don't want to know who it is or any security info, we just want them to remove our banking info from their system!!  If I can't get someone to fix this, I am taking all of our business accounts somewhere else!!!